Codes 33 and 43
Thread Starter
Drifting
Joined: Apr 2004
Posts: 1,453
Likes: 0
From: crystalriver Florida
Codes 33 and 43
Ok---just ran a datalogg on the car, heres what I got....85 vette/383/rebuilt
Code 33-Map High, (manifold air pressure)
Code 43-Knock esc
Not sure what either of these are or where to start looking to fix this, but my car Barely made it home, wasn't responding well at all under throttle, lights would all go off on digicluster everytime the car stumbled and it felt like the car slowed down each time too.... Before this stuff started happening the car ran Excellent!! I've had a rebuild done recently, maybe 5 months ago with about 2k miles on the 85
Code 33-Map High, (manifold air pressure)
Code 43-Knock esc
Not sure what either of these are or where to start looking to fix this, but my car Barely made it home, wasn't responding well at all under throttle, lights would all go off on digicluster everytime the car stumbled and it felt like the car slowed down each time too.... Before this stuff started happening the car ran Excellent!! I've had a rebuild done recently, maybe 5 months ago with about 2k miles on the 85
Pro
Joined: Jun 2004
Posts: 646
Likes: 0
From: Santee Ca
Originally Posted by chillcat
Ok---just ran a datalogg on the car, heres what I got....85 vette/383/rebuilt
Code 33-Map High, (manifold air pressure)
Code 43-Knock esc
Not sure what either of these are or where to start looking to fix this, but my car Barely made it home, wasn't responding well at all under throttle, lights would all go off on digicluster everytime the car stumbled and it felt like the car slowed down each time too.... Before this stuff started happening the car ran Excellent!! I've had a rebuild done recently, maybe 5 months ago with about 2k miles on the 85
Code 33-Map High, (manifold air pressure)
Code 43-Knock esc
Not sure what either of these are or where to start looking to fix this, but my car Barely made it home, wasn't responding well at all under throttle, lights would all go off on digicluster everytime the car stumbled and it felt like the car slowed down each time too.... Before this stuff started happening the car ran Excellent!! I've had a rebuild done recently, maybe 5 months ago with about 2k miles on the 85
Thread Starter
Drifting
Joined: Apr 2004
Posts: 1,453
Likes: 0
From: crystalriver Florida
Map----I ran a datalog directly off my ecm and it had 33 and 43 checked as code errors. And they were labeled, Map-manifold air pressure, and 43 as a knock, the maf plug is not loose
Le Mans Master
Joined: Feb 2006
Posts: 8,753
Likes: 9
From: Louisiana
No problem, but there is no MAP on a 85 vette since it has a MAF. The MAP is used on speed density setup cars. It will benifit you to purchase a FSM for your 85. There is more info in there, than you will ever need or use. Best purchase you will make for your car.
When I run TunerPro RT on my 86 it gives me a MAP reading too. Just ignore it. Code 33 is a MAF code and the 43 is a knock sensor module code. Check the connections at both and even at the ECM, it's free.
When I run TunerPro RT on my 86 it gives me a MAP reading too. Just ignore it. Code 33 is a MAF code and the 43 is a knock sensor module code. Check the connections at both and even at the ECM, it's free.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
codes
I got my book right here
43 is electronic spark control
says you might have an electronic spark control module gone bad, or a knock sensor no good
before doing anything, if you can, use a small hammer and lightly tap engine right next to the knock sensor while the engine is running. check that the engine RPM dips, then goes back to normal idle.
if that does nothing,
1. disconnect battery to clear codes
2. let engine idle for 1 minute or until codes reappear, don't shut it off.
3. gain access to the engine computer and check volts with a
voltmeter on b-7. use a paper clip to back probe it (meter attached)
under 6 volts,
A.turn off engine and go to esc module and disconnect.
B.turn key back on check B on esc connector, should read battery volts
C. if volts are present, there is a bad wire from B-7 to C at esc
connector
over 6 volts
A. bad wire at B-7 (open)
B. if wire good, replace ESC module (over by the heater)
additional info....
43 is electronic spark control
says you might have an electronic spark control module gone bad, or a knock sensor no good
before doing anything, if you can, use a small hammer and lightly tap engine right next to the knock sensor while the engine is running. check that the engine RPM dips, then goes back to normal idle.
if that does nothing,
1. disconnect battery to clear codes
2. let engine idle for 1 minute or until codes reappear, don't shut it off.
3. gain access to the engine computer and check volts with a
voltmeter on b-7. use a paper clip to back probe it (meter attached)
under 6 volts,
A.turn off engine and go to esc module and disconnect.
B.turn key back on check B on esc connector, should read battery volts
C. if volts are present, there is a bad wire from B-7 to C at esc
connector
over 6 volts
A. bad wire at B-7 (open)
B. if wire good, replace ESC module (over by the heater)
additional info....
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Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
codes
code 33 with a mass air sensor
code 33 indicates that the ECM (computer) has seen more than 45 grams of flow per second when:
1. the engine is started
2. or at 1/4 throttle or less
3. rpm is less than 2000 RPM
there are extensive tests to determine the problem.
2 things come up
a. change maf burn off relay
b. change maf power relay
another source of problems, is that the relays are behind the battery, and the battery gasses corrode the ground for the relays. make sure that area and the ground wires are clean.
code 33 indicates that the ECM (computer) has seen more than 45 grams of flow per second when:
1. the engine is started
2. or at 1/4 throttle or less
3. rpm is less than 2000 RPM
there are extensive tests to determine the problem.
2 things come up
a. change maf burn off relay
b. change maf power relay
another source of problems, is that the relays are behind the battery, and the battery gasses corrode the ground for the relays. make sure that area and the ground wires are clean.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
codes
the last thing is to check that the egr valve closed
if it didn't, your car will run like crap because of the exhaust filling the intake manifold
take a long ratchet extension or long screwdriver, and lightly tap the egr valve, and see if the idle improves at all
if it does, clean the egr valve or get a new one
if it didn't, your car will run like crap because of the exhaust filling the intake manifold
take a long ratchet extension or long screwdriver, and lightly tap the egr valve, and see if the idle improves at all
if it does, clean the egr valve or get a new one
